Did clay mould life's origins?

April 4, 2011
By Cath Harris

(PhysOrg.com) -- An Oxford University scientist has taken our understanding of the origin of life a step further.

Professor Don Fraser from the Department of Earth Sciences has carried out neutron scattering experiments to try to find out more about the role of geochemistry in determining the origin of our amino acids  key building blocks of life on Earth  and specifically why the DNA-coded amino acids that make up our proteins are all left-handed.

There are two varieties of amino acids, known as left- or right-handed (referred to as S and R). They are mirror images of each other and both exist in nature, as shown for other substances by Louis Pasteur.

Biochemical processes in living organisms use left- and right-handed or chiral receptors that template differently with these two forms. The olfactory receptors in our noses, for example, easily distinguish the distinct smells of the otherwise identical molecules (called carvones) of spearmint (R-carvone) and caraway (S-carvone).

Another example is the thalidomide tragedy that was related to the presence in the drug of both the mirror-image forms. One of these (S) was later understood to be harmful.

An important and outstanding mystery is why nature chooses only exclusively left-handed amino acids in forming proteins.

In the late 19th century, TH Huxley and Charles Darwin realised that life may have begun abiotically in a warm little pond containing all the elements needed for life, so that a protein compound was chemically formed ready to undergo still more complex changes, Darwin wrote.

Much later, in 1924, the Soviet scientist Alexander Oparin returned to the idea of spontaneous generation, suggesting that a primeval soup of organic molecules, created by the action of sunlight in an oxygen-free environment, was the basis of all life.

Electric spark experiments subsequently carried out by Stanley Miller in model primeval atmospheres showed that amino acids form in lightning discharges. In contrast to biological systems, these show no preference for either mirror image form and are 50%:50% (racemic) mixtures.

Clay was suggested by the crystallographer John Bernal as a means of concentrating primitive biomolecules onto its surface so as to be available for further reactions. Clays again became the focus of studies more recently when James Ferris showed that they can act as catalysts for the formation of long strands of RNA, which with proteins and DNA are major compounds essential for the origin of life.

In a second paper, also published in Physical Chemistry Chemical Physics, Professor Fraser has extended these ideas to consider amino acids and to try to understand why all amino acids used to make proteins are left-handed.

With colleagues Professor Neal Skipper from UCL, Dr Martin Smalley from York University and Dr Chris Greenwell from Durham University he replaced the cations between the layers making up natural clay molecules with weakly bound organic cations, causing the clay layers to drift apart.
That created an extremely sensitive clay system with sufficient space to insert both left-handed and right-handed forms of the amino acid histidine between the layers.

"We found that the R- and S-histidine molecules interact differently with the clay surfaces. These clays are abiotically able to select for chirality  left- or right-handedness  as well as being implicated in the abiotic synthesis of RNA," Professor Fraser says. "Our experiments were the first to show that clay molecules could do that.

"We also found that the tiny interlayer space some 5nm wide was a very important dynamic region for studying prebiotic chemistry and that the reactions of simple chemicals there leads to the formation both of RNA oligomers and the selection of left-handed amino acids.

Clays have also been shown by Jack Szostak and others to enable fatty acids to form primitive cells and, interestingly, clays show similar selective behaviour in space, as reported recently by the NASA scientists Glavin and Dworkin.

Amino acids contained in the meteorites Murchison and Orgueil show enrichment in S-amino acids and this correlates with the amount of intrinsic hydrous clay present in these primitive meteorites that are 4.55 billion years old. The amino acid studied  isovaline  cannot be a contaminant as it is not found in terrestrial living systems, Professor Fraser explains. We are thus building an increasingly detailed picture of the steps that lead to the origin of life.

"We are continuing our research next month on the new NIMROD instrument at the ISIS neutron source near Oxford. This will involve amino acids enriched in deuterium, an isotope of hydrogen, and will provide a detailed atomic picture of the way amino acids interact with the layers of clay for the first time.

"In the long term, this work could have significant applications not only for our understanding of the origin of life, but also in medicine as the design of new mineral surfaces that aid the production of chiral drugs would be of great benefit to the pharmaceutical industry."

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The Bible also states that woman was made from man's rib (I could have sworn it was a cervical vertebra) and that there are unicorn's and dragons. And giants. And witches. And cocatrices.

Don't know about the cockatrice, born of a hen's egg, that kills with a glance, but the world had 4 corners, was centered on Jerusalem and Leviathan ruled the deep.

I don't have a problem with Creative Design as long as you're speculating about the physicists in another Universe who designed the particle accelerator or black hole generator that created the singularity that became our Universe.

I knew about unicorns, dragons, giants, and witches, but hadn't realized about the cockatrice. You have to read the King James version (check out crosswalk.com) and reference Isaiah 11:8 and 59:5 and also Jeremiah 8:17.

Why did my comment about the Qur'an not get posted? The moderator did not want it posted I suppose. In the Qur'an it specifically states in at least 3 places that man was made from clay. Not dirt, not the dust of the earth, but clay. Just Google it and you'll find it.

Why did my comment about the Qur'an not get posted? The moderator did not want it posted I suppose. In the Qur'an it specifically states in at least 3 places that man was made from clay. Not dirt, not the dust of the earth, but clay. Just Google it and you'll find it.

he replaced the cations between the layers making up natural clay molecules with weakly bound organic cations, causing the clay layers to drift apart.

Note that once again the researcher had to interfere with what was available in nature. So NOTHING spontaneous can occur here!

Hence one can point out that any other research done on the modified clay and any results obtained will be as questionable as the study itself. Life is simply far too complex to have ever arisen spontaneously out of some chemical soup.

An important and outstanding mystery is why nature chooses only exclusively left-handed amino acids in forming proteins.

The real mystery is why human beings continue to want life to have arisen spontaneously when all the latest research points to ever-increasing complexity in even the simplest of cells.Nature cannot "choose", only a living intelligent mind can do that. So when will the researcher[and other evolutionists] wake up to there having been a creator?

Nature cannot "choose", only a living intelligent mind can do that. So when will the researcher[and other evolutionists] wake up to there having been a creator?

Scientists and other like-minded individuals (you might call them evolutionists) require Proof before we call something a Fact.

Provide me indisputable proof of your god and i'll go along with it. Until you can do that Religion will continue to wallow in in faith and hope - Neither of which are helpful AT ALL in science.

Most folks who go to church, believe in god, and consider themselves religious, also believe in modern science (Including Evolution). Those who do not, are really just fooling themselves into thinking they're anything but a fringe minority, laughed at even by their fellow Christians.

Do you also think other areas of science are wrong as well? If so list them out, i'm sure we could have a wonderful discussion on those issues as well.

Homochirality can be explained by the variance in temperature or phase of the amino acids. The chirality of life has actually given us some indications of when life arose/where life arose based on when the potential amount of D- amino acids conformed to those conditions, which would be in tidal pools varying between 0 and 120 degrees F or in sub oceanic vents between 30 and 400 degrees F (based on pressure).

The chirality of amino acids also leads to rigid chirality constraints based upon the presence of bonding catalysts in the environment, like the clay mentioned in the article above.

In short, you're saying that life couldn't have arisen because the article above says it can't.

Truth is, the article above says it can and must enforce chirality (if you actually read the paper you'd know this). Stop wanking out that 'answersingenesis' nonsense. It's all been debunked, all of it.

Why did my comment about the Qur'an not get posted? The moderator did not want it posted I suppose. In the Qur'an it specifically states in at least 3 places that man was made from clay. Not dirt, not the dust of the earth, but clay. Just Google it and you'll find it.

Because in our country with the right to free speech, we can burn the flag or the bible but if we burn the qur'an or mention it in a disparaging way, it is a sin, almost as bad as saying the n word.

indications of when life arose/where life arose based on when the potential amount of D- amino acids conformed to those conditions, which would be in tidal pools varying between 0 and 120 degrees F or in sub oceanic vents between 30 and 400 degrees F (based on pressure).

Pretty specific range there. Wish my qualification time for Boston was in that range. A 2:24 up to a 6:45 would qualify me. Yippie.

Less than impressed with the article. No mention made of why the selection effect occurs. I was under the impression that clay wasn't chiral, or if it is , it occurs in a racemic mixture. I have never heard of left-handed clay or right-handed clay. It shouldn't interact differently with mirror image molecules, and my bet is that their clay was contaminated with something chiral, probably something of biological origin.